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This paper presents the first built-in self-test system (BIST) for W-band transmit–receive phased-array modules. Low-loss high-isolation switches are attached to the RF input and output ports using \lambda/4 transmission-line sections, which result in a high shunt impedance when the BIST is disabled and minimal penalty in additional loss. A W-band in-phase/quadrature down-conversion mixer/receiver with <0.5-dB amplitude and 4^\circ–5^\circ phase imbalance at 90–100 GHz is also implemented on-chip and is used as an on-chip vector network analyzer. The BIST allows the measurement of the normalized S21 in both transmit and receive modes with high accuracy (4-bit phase response, <0.5-dB amplitude variation) at 90–100 GHz without any external calibration. The BIST also results in a normalized frequency response that agrees well with the measured S-parameters at 90–100 GHz. [ABSTRACT FROM PUBLISHER]

This paper presents a 4 \times 4 transmit/receive (T/R) SiGe BiCMOS phased-array chip at 90–100 GHz with vertical and horizontal polarization capabilities, 3-bit gain control (9 dB), and 4-bit phase control. The 4 \times 4 phased array fits into a \ 1.6\times \ 1.5\ \ mm^2 grid, which is required at 94 GHz for wide scan-angle designs. The chip has simultaneous receive (Rx) beam capabilities (V and H) and this is accomplished using dual-nested 16:1 Wilkinson combiners/divider with high isolation. The phase shifter is based on a vector modulator with optimized design between circuit level and electromagnetic simulation and results in <1 dB and <\ 7.5^\circ\ \rms gain and phase error, respectively, at 85–110 GHz. The behavior of the vector modulator phase distortion versus input power level is investigated and measured, and design guidelines are given for proper operation in a transmit (Tx) chain. The V and H Rx paths result in a gain of 22 and 25 dB, respectively, a noise figure of 9–9.5 (max. gain), and 11 dB (min. gain) measured without the T/R switch, and an input P1\ {dB} of -31 to -26 dBm over the gain control range. The measured output Psat is \sim-5 dBm per channel, limited by the T/R switch loss. Measurements show \pm0.6- and \pm0.75-dB variation between the 4 \times 4 array elements in the Tx mode ( Psat) and Rx mode, respectively, and <-40-dB coupling between the different channels on the chip. The chip consumes 1100 mA from a 2-V supply in both the Tx and Rx modes. The design can be scaled to >10 000 elements using polyimide redistribution layers on top of the chip and the application areas are in W-band radars for landing systems. [ABSTRACT FROM PUBLISHER]